The applicant claims priority under 35 U.S.C. .sctn. 119 based upon European Patent Application No. 96106958.0 filed in the European Patent Office on May 3, 1996. The invention relates to a method of producing a guide wire, in particular for the percutaneous introduction of a balloon dilation catheter into a blood vessel, in which the guide wire has a flexible coil which surrounds a likewise flexible shaft and is produced from at least two coil springs which are rotated together at a connection location over a plurality of turns and are soldered to one another. Moreover, the invention relates to a guide wire, in particular for the percutaneous introduction of a balloon dilation catheter into a blood vessel, having a flexible coil which surrounds a likewise flexible shaft and is produced from at least one distal and one proximal coil spring, which coil springs are rotated together at a connection location over a plurality of turns and are soldered to one another.
Numerous embodiments of guide wires of the type are known in the prior art and are used, in particular, for the percutaneous introduction of a balloon dilation catheter into a blood vessel, in particular a constriction in such a vessel. In order for the guide wire to be suitable for introducing a balloon dilation catheter into a constriction in a blood vessel, it must have, in addition to a high operational reliability, special properties, and in particular it must be controllable and very flexible at the distal end. Moreover, the guide wire should have a region which is visible to X-rays which is comparatively short and sharply defined.
A guide wire of this kind is disclosed, for example, in U.S. Pat. No. 4,748,986. This guide wire has a coil which comprises a distal coil spring which is visible to X-rays and a proximal coil spring. The coil surrounds a shaft which at the distal end is conically tapered and connected to a tip. In order to connect the two coil springs, the latter are rotated together at the ends to be connected over a plurality of turns and are soldered continuously to the shaft and a safety strip. This joining of the coil springs and the soldering represent an extremely complex and, in particular, time-intensive manual operation. Due to the comparatively solid solder region, the guide wire is significantly less flexible at the connection location than in front of and behind this region. As a result, the controllability of the guide wire is impaired. In order to improve the desired properties of the guide wire, it has been proposed in U.S. Pat. No. 5,429,139 to connect the two coil springs by means of a connection coil. After stretching the turns to be connected and inserting the flexible shaft, this comparatively short connection coil is rotated in and soldered. This has the effect, inter alia, that the flexibility of the guide wire is impaired to a lesser extent by the connection location. However, the time required to connect the two coil springs is comparatively high, it being necessary to take into account the extreme fineness of the coil springs to be connected and the high demands placed on the reliability of the connection location.
EP-A-0,419,277 shows a further possibility for connecting two coil springs. This method uses an intermediate piece which has grooves on the outside, onto which grooves the coil-spring ends to be connected are rotated.
Various guide wires are shown in U.S. Pat. Nos. 4,934,380; 5,282,478; and 5,415,170.
All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties for all purposes.